Opthalmoscope device

ABSTRACT

An example eye fundus imaging apparatus can include: a display device; an image capture device configured to capture at least one image of a fundus of an eye; and a control module programmed to: display a target, the target indicating a desired position for the image capture device to capture the at least one image of the fundus of the eye; monitor a relative position of the eye with respect to the target; and when the relative position of the eye corresponds to the target, automatically capture the at least one image of the fundus of the eye.

BACKGROUND

An ophthalmoscope is device used to image the fundus (or eye fundus) andother structures of the eye. This imaging is used to determine thehealth of the retina and vitreous humor and to evaluate conditions suchas hypertension, diabetic retinopathy, and papilledema. Theophthalmoscope device may include a camera that is used to capture theimages and a display used to display the images obtained by theophthalmoscope device. The eye must be aligned properly with the deviceto capture fundus images.

Typically the ophthalmoscope is a hand-held device or a headband-mounteddevice that is worn by a caregiver.

SUMMARY

In one aspect, a wearable device configured to capture eye fundus imagescomprises: a support structure configured to be worn by a subject; adisplay device coupled to the support structure, the display deviceconfigured to overlay an overlay image in a field of view of thesubject; and an image capture device coupled to the support structure,the image capture device configured to capture images of an eye fundusof the subject.

In another aspect, a wearable device configured to capture eye fundusimages comprises: a support structure configured to be worn by asubject; a display device coupled to the support structure, the displaydevice configured to overlay an overlay image in a field of view of thesubject, the display device comprising: a projector configured toproject a pattern of light representing the overlay image; and a prismdisposed in the field of view of the subject, the prism configured todirect at least a portion of the pattern of light towards an eye fundusof the subject; an image capture device coupled to the supportstructure, the image capture device configured to capture images of theeye fundus through the prism of the display device; and a control moduleprogrammed to: instruct the image capture device to capture a pluralityof images in a first image capture mode; process at least a portion ofthe plurality of images to determine a position of a pupil of thesubject; and instruct the image capture device to capture an image in asecond image capture mode when the position of the pupil issubstantially aligned with an optical axis of the image capture device,wherein: the first image capture mode comprises a first resolution and afirst illumination condition; the second image capture mode comprises asecond resolution and a second illumination condition; the secondresolution is greater than or equal to the first resolution; and thesecond illumination condition is brighter than the first illuminationcondition.

In yet another aspect, a method for capturing an eye fundus image of asubject using a wearable ophthalmoscope, comprises: securing thewearable ophthalmoscope to the subject; capturing a plurality of images,by the wearable ophthalmoscope, of a pupil of the subject, wherein theplurality of images are captured in a first image capture mode;processing at least a portion of the plurality of images to determine aposition of the pupil; and capturing an eye fundus image of the subjectwhen the position of the pupil is in a desired position, wherein the eyefundus image is captured in a second image capture mode.

DESCRIPTION OF THE FIGURES

FIG. 1 shows an example system for performing ophthalmoscopy procedures.

FIG. 2 shows an example ophthalmoscope device of the system of FIG. 1.

FIG. 3 shows an example display device and image capture device of theophthalmoscope device of FIG. 2.

FIG. 4 shows an example of a subject wearing an example of theophthalmic device of FIG. 2.

FIG. 5 shows another example of a subject wearing an example of theophthalmic device of FIG. 2.

FIG. 6 shows an example of a subject wearing another embodiment of theophthalmic device of the system of FIG. 1.

FIG. 7 shows an example of the ophthalmic device of FIG. 2 and an eye ofa subject.

FIG. 8 shows an example of the ophthalmic device of FIG. 6 and an eye ofa subject.

FIG. 9 shows an example of the image capture device of FIG. 3 and theeye of a subject.

FIG. 10 shows another example of the image capture device of FIG. 3 andthe eye of a subject.

FIG. 11 shows an example process of capturing eye fundus images with thesystem of FIG. 1.

FIG. 12 shows another example process of capturing eye fundus imageswith the system of FIG. 1.

FIG. 13 shows an example cursor sequence from the process of FIG. 12.

FIG. 14 shows another example process of capturing eye fundus imageswith the system of FIG. 1.

FIG. 15 shows an example sequence of cursor positions from the processof FIG. 14

FIG. 16 shows another example process of capturing eye fundus imageswith the system of FIG. 1.

FIG. 17 shows another example system for performing ophthalmoscopyprocedures.

FIG. 18 shows an example system for performing ophthalmoscopyprocedures.

FIG. 19 shows a method of capturing eye fundus images with the systemsof FIG. 17 and FIG. 18.

DETAILED DESCRIPTION

The present disclosure relates to an ophthalmoscope device and methodsfor capturing images from ophthalmoscope devices. In some embodiments,the ophthalmoscope device is worn by the subject of the images. In otherembodiments, the ophthalmoscope device is held by a caregiver. Theophthalmoscope device captures images of the fundus (or eye fundus) ofthe subject through the subject's pupil. Often the fundus images includethe fovea. The ophthalmoscope device captures these images when thesubject's eye is oriented to provide a line of site through the pupil tothe fundus and fovea.

FIG. 1 is an example system 100 for performing ophthalmoscopyprocedures. In this example, an ophthalmoscope device 102 is configuredto be worn by a subject or wearer and to capture eye fundus images ofthat subject. In other examples, the ophthalmoscope device 102 isconfigured to be held by the hand of a caregiver. In some embodiments,the ophthalmoscope device 102 is used to capture digital images. Inother embodiments, the ophthalmoscope device 102 is used to capture filmimages.

In addition, in some embodiments, the ophthalmoscope device 102 isconfigured to send data associated with the digital images to a centralserver 106. For example, the ophthalmoscope device 102 can be programmedto send digital images to the central server 106 for additionalprocessing and/or storage in an electronic medical record (EMR).

The ophthalmoscope device 102 and the central server 106 communicatethrough a network 104. In one example, the ophthalmoscope device 102 andnetwork 104 are part of a CONNEX™ system from Welch Allyn of SkaneatelesFalls, N.Y., although other systems can be used. In such an example, themonitor devices communicate through known protocols, such as the WelchAllyn Communications Protocol (WACP). WACP uses a taxonomy as amechanism to define information and messaging. Taxonomy can be definedas description, identification, and classification of a semantic model.Taxonomy as applied to a classification scheme may be extensible.Semantic class-based modeling utilizing taxonomy can minimize thecomplexity of data description management by limiting, categorizing, andlogically grouping information management and operational functions intofamilies that contain both static and dynamic elements.

In another example, the central server 106 can be a distributed network,commonly referred to as a “cloud” server. The ophthalmoscope device 102communicates with the cloud server through non-proprietary, industrystandard messaging. Data encryption is also based on industry standards.

The network 104 is an electronic communication network that facilitatescommunication between the ophthalmoscope device 102 and the centralserver 106. An electronic communication network is a set of computingdevices and links between the computing devices. The computing devicesin the network use the links to enable communication among the computingdevices in the network. The network 104 can include routers, switches,mobile access points, bridges, hubs, intrusion detection devices,storage devices, standalone server devices, blade server devices,sensors, desktop computers, firewall devices, laptop computers, handheldcomputers, mobile telephones, and other types of computing devices.

In various embodiments, the network 104 includes various types of links.For example, the network 104 can include wired and/or wireless links,including Bluetooth, ultra-wideband (UWB), 802.11, ZigBee, and othertypes of wireless links. Furthermore, in various embodiments, thenetwork 104 is implemented at various scales. For example, the network104 can be implemented as one or more local area networks (LANs),metropolitan area networks, subnets, wide area networks (such as theInternet), or can be implemented at another scale. Additionally, thenetwork 104 includes networks formed between the ophthalmoscope device102 and a peripheral device using a wireless network protocol (e.g., amouse connected using Bluetooth, etc.).

The ophthalmoscope device 102 and the central server 106 are computingdevices. A computing device is a physical, tangible device thatprocesses data. Example types of computing devices include personalcomputers, standalone server computers, blade server computers,mainframe computers, handheld computers, smart phones, special purposecomputing devices, and other types of devices that process data.

Computing devices can include at least one central processing unit(“CPU”), a system memory, and a system bus that couples the systemmemory to the CPU. The system memory includes a random access memory(“RAM”) and a read-only memory (“ROM”). A basic input/output systemcontaining the basic routines that help to transfer information betweenelements within the device, such as during startup, is stored in theROM. The device further includes a mass storage device. The mass storagedevice is able to store software instructions and data.

The mass storage device and its associated computer-readable datastorage media provide non-volatile, non-transitory storage for thedevice. Although the description of computer-readable data storage mediacontained herein refers to a mass storage device, such as a hard disk orCD-ROM drive, it should be appreciated by those skilled in the art thatcomputer-readable data storage media can be any availablenon-transitory, physical device or article of manufacture from which thedevice can read data and/or instructions.

Computer-readable data storage media include volatile and non-volatile,removable and non-removable media implemented in any method ortechnology for storage of information such as computer-readable softwareinstructions, data structures, program modules or other data. Exampletypes of computer-readable data storage media include, but are notlimited to, RAM, ROM, EPROM, EEPROM, flash memory or other solid statememory technology, CD-ROMs, digital versatile discs (“DVDs”), otheroptical storage media, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices, or any other medium which canbe used to store the desired information and which can be accessed bythe device.

The computing device can also include an input/output controller forreceiving and processing input from a number of other devices, includinga keyboard, a mouse, a touch user interface display screen, or anothertype of input device. Similarly, the input/output controller providesoutput to a touch user interface display screen, a printer, or othertype of output device.

Referring now to FIG. 2, the ophthalmoscope device 102 is shown in moredetail. In this example, the ophthalmoscope device 102 includes asupport structure 130, a control module 132, a display device 134, animage capture device 136, and an illumination device 138.

The support structure 130 is a physical structure that holds the othercomponents of the ophthalmoscope device 102 and, in some embodiments, isconfigured to couple to the wearer. In some embodiments, the supportstructure 130 is an eye glasses frame. In other embodiments, the supportstructure 130 is a headband. In some embodiments, the support structure130 is formed from a rigid material, such as some plastics, metals, orcomposites. In other embodiments, the support structure 130 is formedfrom a semi-rigid or flexible material, such as rubber, elastic, or someplastics. In yet other embodiments, the support structure 130 is formedfrom a combination of materials, including rigid materials, semi-rigidmaterials, and flexible materials. Other embodiments of the supportstructure 130 are possible as well. Although the support structure 130described in this embodiment is configured to be coupled to the wearer,in other embodiments the support structure 130 is configured to be heldin a hand of a caregiver. The support structure 130 is an example of ahousing.

The control module 132 is a module configured to control the operationof the ophthalmoscope device 102. The control module 132 can include acomputing device. In some embodiments, the control module 132 controlsthe operation of the display device 134, the image capture device 136,and the illumination device 138.

The display device 134 is a device configured to display images orpatterns of light that are visible to the wearer of the ophthalmoscopedevice 102. The display device 134 is shown and described in greaterdetail with respect to FIGS. 3-8. In some embodiments, the displaydevice 134 is the display included in Google Glass from Google Inc. ofMountain View, Calif.

The image capture device 136 is a device configured to capture images ofthe wearer of the ophthalmoscope device 102. In some embodiments, theimage capture device 136 includes a camera or image capture sensor, suchas a charge-coupled device or complementary metal-oxide-semiconductor.In some embodiments, the image capture device 136 includes a digitalvideo camera. Yet other embodiments of the image capture device 136 arepossible as well. In the examples shown, the image that is captured is adigital image. In the example shown, the image capture devices cancapture images in a variety of formats, such as JPEG, BITMAP, TIFF, etc.The image capture device 136 is shown and described in greater detailwith respect to FIGS. 3 and 6-10.

The illumination device 138 is a device configured to generate anddirect light towards the eye of the wearer of the ophthalmoscope device102 so that the structures of the eye may be imaged. In someembodiments, the illumination device 138 comprises one or more lightemitting diodes, incandescent bulbs, or fiber optic cables. Yet otherembodiments of the illumination device 138 are possible as well. In someembodiments, the illumination device 138 is configured to createmultiple illumination conditions, each having a different intensity(i.e., brightness) of light. However, some embodiments of theophthalmoscope device 102 do not include an illumination device 138.

Referring now to FIG. 3, embodiments of the display device 134 and theimage capture device 136 of the ophthalmoscope device 102 are shown inmore detail. The display device 134 includes a projector 160 and a prism162. The image capture device includes a lens 164. Also shown areprojected light rays 166.

The projector 160 is an optical device that projects images or light. Insome embodiments, the projector 160 receives electronic signalscorresponding to images and projects patterns of light corresponding tothose images. In the embodiment shown, the projector projects images orlight through a surface of the prism 162.

The prism 162 is an optical element and is configured to refract lightrays that enter through one of its surfaces out through a differentsurface. In the embodiment shown, the prism 162 refracts the projectedlight rays 166 projected by the projector by approximately ninetydegrees. In some embodiments, the prism 162 is transparent orsemi-transparent.

The lens 164 is an optical device that transmits and directs light raysfrom outside the image capture device 136 into the image capture device136. In the embodiment shown, the lens 164 is disposed to receive lightrays that pass through the prism 162.

Referring now to FIG. 4, an illustration of a subject S wearing anembodiment of the ophthalmoscope device 102 is shown. Also shown is thefield of view V of the subject S.

In the embodiment shown, the subject S is wearing the ophthalmoscopedevice 102 like a pair of glasses. The device rests on the bridge of thenose of the subject S and includes arms that wrap around the head of thesubject S. In some embodiments, the arms rest on the ears of the subjectS.

The field of view V illustrates an overlay layer 200. The overlay layer200 corresponds to the portion of the field of view V in which thedisplay device 134 may overlay images. In the example shown an image ofa cursor 202 is displayed in the field of view V of the subject S on theoverlay layer 200. In some embodiments, the overlay layer 200 istransparent or translucent. Accordingly, on portions of the overlaylayer 200 that are not displaying an image, the field of view V of thesubject S is not occluded. In some embodiments, the overlay layer 200 isnot transparent or translucent and the field of view V of the subject Sis occluded even when images are not being displayed. Additionally, insome embodiments, the image capture device 136 (not shown in thisfigure) occludes the field of view V of the subject S even when theoverlay layer 200 is transparent or translucent. In some embodiments,the overlay layer 200 is the same size as the field of view V.

Referring now to FIG. 5, a front-view illustration of a subject Swearing an embodiment of the ophthalmoscope device 102 is shown. Asshown in this figure, the projected light rays 166 are refracted by theprism 162. After being refracted, the projected light rays 166 passthrough the pupil P of the subject S and contact the retina R of thesubject S. If the subject S is focusing on the image being projected bythe projector 160, the eye of the subject S will be oriented such thatthe projected light rays 166 will contact the fovea F of the subject S.The fovea F is the region of the retina R where vision is are sharpest.It is located in the center of the macula region of the retina R.

Referring now to FIG. 6, a top-view illustration of a subject S wearinganother embodiment of the ophthalmoscope device 230 is shown. In thisillustration, the image capture device 136, lens 164, reflection device240, and image light rays 242 are shown. The ophthalmoscope device 230is similar to the ophthalmoscope device 102 except that it includes thereflection device 240 and the image capture device 136 is disposed on aside of that reflection device 240.

The reflection device 240 is an optical device and is configured todirect the image light rays 242 into the lens 164 of the image capturedevice 136. In some embodiments, the reflection device 240 is a prism.In other embodiments, the reflection device 240 is a mirror. Otherembodiments of the reflection device 240 are possible as well.

The image light rays 242 are light rays that are reflected by thevarious eye structures. At least a portion of the image light rays 242are captured by the image capture device 136 to generate an image.

Although in the embodiment shown in FIG. 6, the image capture device 136is disposed on the opposite side of the reflection device 240 from theprojector 160, in other embodiments, the image capture device 136 isdisposed in other locations, such as next to the projector 160.

Referring now to FIG. 7, a top-view illustration of an embodiment of theophthalmoscope device 102 and an eye E of a subject S. Also shown areprojected light rays 166, image light rays 242, and environment lightrays 270 a-b. The environment light rays 270 a-b include light rays fromambient light sources.

The projector 160 is configured to project projected light rays 166 intothe prism 162, where the projected light rays 166 are refracted towardsthe eye E. Because the projector 160 is disposed on the side of theprism 162, it does not occlude the subject's view significantly.

The image capture device 136 is disposed across the prism 162 from theeye E. The lens 164 is configured to image the eye E through the prism162. The lens 164 transmits image light rays 242 into the image capturedevice 136 for imaging. The image light rays 242 pass are reflected bythe eye E and pass through the prism 162 to reach the lens 164. Theimage light rays 242 pass through the prism 162.

Additionally, some of the environment light rays 270 a-b also reach theeye E. In this manner, the subject can perceive the environment whilealso perceiving the projected light rays 166. However, only some of theenvironment light rays 270 a-b reach the eye E, because the imagecapture device 136 occludes the subjects field of view. For example,environment light ray 270 a is not occluded by the image capture device136 and reaches the eye E. Conversely, environment light ray 270 b isoccluded by the image capture device 136 and does not reach the eye E.In some embodiments, the environment light rays 270 a-b are occluded toreduce the chance of glare.

Referring now to FIG. 8, another top-view illustration of an embodimentof the ophthalmoscope device 230 and an eye E of a subject S. Also shownare projected light rays 166, image light rays 242, and environmentlight rays 270 a-b.

Although the image light rays 242 pass through the prism 162 withoutbeing refracted significantly, the image light rays 242 are refracted bythe reflection device 240. In this manner, the image light rays 242 areredirected by the reflection device 240 into the lens 164 for imaging bythe image capture device 136.

In this embodiment, neither the projector 160 nor the image capturedevice 136 significantly occlude the field of view of the subject S.Further, the embodiment of reflection device 240 shown allows at least aportion of the light proximate to the subject to reach the eye E. Asshown, both of the environment light rays 270 a and 270 b reach the eyeE.

Referring now to FIG. 9, a top view illustration of an arrangement of anembodiment of the image capture device 136 and an eye E of a subject Sis shown. Also shown are the optical axis 290 of the image capturedevice 136 and the pupil/fovea orientation axis 292.

In the arrangement shown, the pupil/fovea orientation axis 292 isaligned with the optical axis 290 of the image capture device 136.Accordingly, in this arrangement, the image capture device 136 cancapture a fundus image that includes the fovea F, which is oftendesired.

The optical axis 290 of the image capture device 136 is not a physicalstructure, but instead refers to the axis about which the image capturedevice 136 receives optical information. Generally, the optical axis 290runs through the center of the lens 164 and is perpendicular to thesurface at the center of the lens 164. In embodiments where the imagecapture device 136 is configured to capture image light rays 242 thathave been refracted by the reflection device 240, the optical axis 290is also refracted similarly.

The pupil/fovea orientation axis 292 is not a physical structure, butinstead refers to an axis formed between the fovea F and the pupil P ofthe eye E. It corresponds to the orientation of the eye E.

Referring now to FIG. 10, a top view illustration of an arrangement ofan embodiment of the image capture device 136 and an eye E of a subjectS is shown. Also shown are the optical axis 290 of the image capturedevice 136, the pupil/fovea orientation axis 292, and the angle 294.

In the arrangement shown, the angle 294 represents the differencebetween the pupil/fovea orientation axis 292 and the optical axis 290.In some embodiments, if angle 294 is less than 2-15 degrees, the opticalaxis 290 and the pupil/fovea orientation axis 292 are consideredsubstantially aligned. In other embodiments, optical axis 290 and thepupil/fovea orientation axis 292 are compared to a larger or smallerangle to determine whether they are substantially aligned. In theseembodiments, the image capture device 136 may capture a fundus image ifthe optical axis 290 and the pupil/fovea orientation axis 292 aredetermined to be substantially aligned.

In other embodiments, the image capture device 136 may capture a fundusimage if the position of the pupil P is substantially aligned with anoptical axis 290. In some embodiments, the pupil P is considered to besubstantially aligned with the optical axis 290 when the optical axis290 crosses the pupil P. In some embodiments, the illumination leveldetected by the image capture device 136 is used to determine whetherthe optical axis 290 is aligned with the pupil P and whether the imagecapture device 136 is able to see through the pupil P. In someembodiments, at least a portion of the images captured by the imagecapture device are processed by an automatic thresholding algorithm,such as Otsu's method, to binomially separate the image into regionsbased on illumination levels. The resulting binomially separated regionsor the histogram of detected illumination levels can then be used todetermine whether the image capture device 136 is seeing through thepupil P to the fundus.

In some embodiments, if the pupil/fovea orientation axis 292 is notsubstantially aligned with the optical axis 290 of the image capturedevice 136, the angle 294 is measured and used to guide the eye E to adesired orientation for fundus imaging.

Referring now to FIG. 11, a process 300 performed using some embodimentsof the ophthalmoscope device 102 is shown. The process 300 operates toimage the fundus of the subject S using passive eye tracking. In theprocess 300, the ophthalmoscope device 102 monitors the pupil/foveaorientation of the subject S. Although the process 300 is described withrespect to ophthalmoscope device 102, the process 300 may be performedusing a wearable or nonwearable ophthalmoscope, such as a handhelddigital ophthalmoscope.

Initially, at step 302, the pupil or fovea or both of the subject S aremonitored. The image capture device 136 captures images in a first imagecapture mode. In the first image capture mode, the image capture device136 captures images at a higher frame rate. In some embodiments, in thefirst image capture mode, the image capture device 136 captures imageswith lower illumination and at lower resolutions. In some embodiments,the lower illumination is created by the illumination device 138operating to generate and direct light of a lower intensity towards thesubject. In other embodiments, the lower illumination is created by anexternal light source or ambient light. Additionally, in otherembodiments, the lower illumination is created by the display device134. The first image capture mode may minimize discomfort to the subjectS, allow the subject S to relax, and allow for a larger pupil sizewithout dilation (non-mydriatic).

Next, at step 304, the control module 132 processes at least a portionof the images captured by the image capture device 136. The controlmodule 132 processes the images to identify the location of the pupil orfovea or both of the subject S. Using the location of the pupil or foveaor both in one of the images, a vector corresponding to the pupil/foveaorientation is calculated. In some embodiments, the pupil/foveaorientation is approximated based on the distance between the pupil andfovea in the image. In other embodiments, the pupil/fovea orientation iscalculated by approximating the position of the fovea relative to thepupil in three dimensions using estimates of the distance to the pupiland the distance between the pupil and the fovea. In other embodiments,the pupil/fovea orientation is approximated from the position of thepupil alone. In yet other embodiments, other methods of approximatingthe pupil/fovea orientation are used.

Next, at step 306, the pupil/fovea orientation is compared to theoptical axis of the image capture device 136. If the pupil/foveaorientation is substantially aligned with the optical axis of the imagecapture device 136, the process proceeds to step 308 to capture a fundusimage. If not, the process returns to step 302 to continue to monitorthe pupil or fovea. In some embodiments, the pupil/fovea orientation issubstantially aligned with the optical axis when the angle between themis less than two to fifteen degrees.

Next, at step 308, a fundus image is captured. In some embodiments, thefundus image is captured in a second image capture mode. In someembodiments, in the second image capture mode, the image capture device136 captures images with higher illumination and at higher resolutions.In some embodiments, the higher illumination is created by theillumination device 138 operating to generate and direct light of ahigher intensity towards the subject. In other embodiments, the higherillumination is created by an external light source or ambient light.Additionally, in other embodiments, the higher illumination is createdby the display device 134. The second image capture mode may facilitatecapturing a clear, well-illuminated, and detailed fundus image.

In some embodiments, after step 308, the process 300 returns to step 302to continue to monitor the pupil/fovea orientation. The process 300 maycontinue to collect fundus images indefinitely or until a specifiednumber of images have been collected.

Referring now to FIG. 12, a process 340 performed using some embodimentsof the ophthalmoscope device 102 is shown. The process 340 operates toimage the fundus of the subject S using open-loop reverse eye tracking.The process 340 is similar to the process 300 illustrated and describedwith respect to FIG. 11, except that a cursor sequence is overlaid onthe field of view of the subject S.

Initially, at step 342, the display device 134 begins to overlay acursor sequence in the field of view of the subject. The cursor sequenceincludes a plurality of frames wherein an overlay image of a cursor isdisposed at different locations. The display device 134 continues todisplay the cursor sequence throughout the process 340. During theprocess 340, the subject may be instructed to follow the cursor. Thecursor sequence is designed to orient the pupil and fovea of the subjectfor fundus imaging. An example cursor sequence is shown and described ingreater detail with respect to FIG. 13.

Next, in steps 302-308, a fundus image is captured as described withrespect to FIG. 11.

Referring now to FIG. 13, an example cursor sequence 360 on the overlaylayer 200 is illustrated. The cursor sequence 360 corresponds to aplurality frames that are displayed on the overlay layer. The framesillustrate the cursor at different locations on the overlay layer 200.

In the example cursor sequence 360, a cursor is initially shown at thestarting position 362. In the frames that follow, the cursor moves alongthe path 364 until it reaches the ending position 366. The path 364spirals into the ending position 366. In this manner, the pupil/foveaalignment of the subject S following the cursor will be drawn into manypotential orientations for imaging.

The path 364 is just one example cursor sequence. In other embodiments,other cursor sequences are used.

Referring now to FIG. 14, a process 400 performed using some embodimentsof the ophthalmoscope device 102 is shown. The process 400 operates toimage the fundus of the subject S using closed-loop reverse eyetracking. The process 400 is similar to the process 340 illustrated anddescribed with respect to FIG. 12, except that the cursor sequence isdynamically generated based on determining the pupil/fovea alignment.

Initially, at step 402, the display device 134 overlays a cursor imagein the field of view of the subject. During the process 400, the subjectmay be instructed to follow the cursor. The display device 134 continuesto display the cursor at various locations throughout the process 400.

Next, in steps 302-306, the pupil/fovea orientation is determined andcompared to the optical axis of the image capture device 136 asdescribed with respect to FIG. 11. If the pupil/fovea orientation issubstantially aligned with the optical axis of the image capture device136, the process proceeds to step 308 to capture a fundus image asdescribed with respect to FIG. 11. If not, the process continues tosteps 404-406 to reposition the cursor.

At step 404, a delta vector between the pupil/fovea orientation axis 292and the optical axis 290 is determined. The delta vector corresponds tothe difference in position between the current location of the pupil anda desired location of the pupil for fundus imaging. In some embodiments,the desired location is an estimated optimal location for imaging of thefundus.

Next, at step 406, the cursor is repositioned by a vector thatcorresponds to the delta vector. In some embodiments, the vector bywhich the cursor is repositioned on the overlay layer 200 is calculatedby scaling the delta vector by a factor that correlates a distance onthe overlay layer 200 to a pupil movement distance. After the cursor isrepositioned, steps 302-306 are repeated to determine whether thepupil/fovea is now aligned for imaging the fundus. If not, steps 404-406are repeated again as well. These steps are repeated until the fundusimage can be captured. An example sequence of cursor positions is shownand described in greater detail with respect to FIG. 15.

Referring now to FIG. 15, an example sequence of cursor positions on theoverlay layer 200 is illustrated. Each of the cursor positions showncorresponds to a cursor location during various example iterations ofprocess 400.

In the example, the cursor starts at position 440. After determining instep 306 that the pupil/fovea orientation is not aligned for fundusimaging, the cursor is repositioned to location 442. These steps repeatas the cursor moves to positions 444,446, and finally 448. When thecursor is display at position 448, step 306 determines that thepupil/fovea orientation is aligned properly for fundus imaging.Accordingly, the fundus image is captured.

The cursor positions shown in FIG. 15 are merely examples. In variousembodiments, the cursor may be displayed in other positions as well.

Referring now to FIG. 16, a process 470 performed using some embodimentsof the ophthalmoscope device 102 is shown. The process 470 operates toimage the fundus of the subject S while eliminating glare. Glare (i.e.,light reflected off of the surface of the eye of the subject) mayinterfere with imaging the fundus.

Initially, at step 472, the device 102 generates an imaging condition.In some embodiments, the imaging condition is generated by the displaydevice 134 displaying an illumination pattern. The illumination patternis a pattern of light designed to illuminate the eye or a portion of theeye of the subject S. In some embodiments, the illumination patternincludes bright dots or bright regions on the overlay layer. Otherembodiments of the illumination pattern are possible as well. In otherembodiments, the illumination pattern is generated by the illuminationdevice 138 instead of or in addition to the display device 134.

Next, at step 302, the pupil or fovea or both of the subject S aremonitored as described with respect to FIG. 11.

Next, at step 474, the control module 132 processes at least a portionof the images captured by the image capture device 136. The controlmodule 132 processes the images to identify regions of glare in theimage. Glare regions may be detected using various image processingtechniques. For example, in some embodiments, glare regions are detectedas regions of the image with a saturation level above a definedthreshold. Other embodiments of the glare detection step are possible aswell.

Next, at step 476, the regions of glare are evaluated to determinewhether they will interfere with imaging of the fundus. In someembodiments, this step is performed by determining whether the fovea isvisible despite the regions of glare in the image. If the detectedregions of glare interfere with fundus imaging, step 478 is performed toadjust the illumination pattern. If not, step 308 is performed asdescribed with respect to FIG. 11 to capture a fundus image.

At step 478, the imaging condition is adjusted. In some embodiments, theimaging condition is adjusted by adjusting the illumination pattern. Insome embodiments, the illumination pattern is adjusted according to apre-defined sequence. For example, some embodiments include a sequenceof pre-defined illumination patterns that may be displayed duringprocess 470 as necessary. In other embodiments, the illumination patternis adjusted based on determining a delta vector for a glare region. Forexample, the delta vector may correspond to the difference between thecurrent glare region and a location where the glare would not interferewith imaging the fundus. After the illumination pattern is adjusted,steps 302, 474, and 476 are repeated to determine if the fundus imagecan be captured with the adjusted illumination pattern.

In other embodiments, glare is removed by adjusting the view angle ordepth of field of the image capture device 136. For example, in someembodiments, the depth of field is adjusted by moving the lens 164 alongthe optical axis 290 towards or away from the subject S, such as withauto-focusing mechanisms. Additionally, in some embodiments, the viewangle of the image capture device 136 is adjusted using opticalstabilizer technologies, such as double prism actuators or directionactuated fluid lenses. In these embodiments, the imaging condition ofstep 472 comprises first configurations of the view angle and depth offield. If detected glare prevents imaging of the fundus, the imagingcondition is adjusted by adjusting the depth of field, the view angle,or both in step 478. Then another image is captured. This processrepeats until an image is captured where glare does not prevent imagingof the fundus. In some embodiments, the configurations of the depth offield and view angle are adjusted according to a pre-defined sequence.In other embodiments, the configurations of the depth of field and viewangle are adjusted based on determining a delta vector for a glareregion.

FIG. 17 is another example system 500 for performing ophthalmoscopyprocedures. The example system 500 includes the ophthalmoscope device102, an external display device 502, and an external input device 504.

The ophthalmoscope device 102 is a wearable device to capture images ofthe eye fundus and is illustrated and described in greater detail withrespect to FIGS. 2-8. In system 500, the ophthalmoscope device 102 isconfigured to transmit images it captures to the external display device502 and to receive input commands from the external input device 504.

In some embodiments, the ophthalmoscope device 102 also transmits alocation corresponding to the location of the cursor on the overlaylayer 200 to the external display device 502. In some embodiments, thecursor location is transmitted as part of the image. For example, insome embodiments, the cursor is overlaid on the transmitted images. Inother embodiments, the cursor location is transmitted as coordinateinformation.

In various embodiments, the external display device 502 is implementedas various types of display devices. Example types of display devicesinclude, but are not limited to, cathode-ray tube displays, LCD displaypanels, plasma screen display panels, touch-sensitive display panels,LED screens, projectors, and other types of display devices. Theexternal display device 502 is configured to receive and display imagestransmitted by the ophthalmoscope device 102. In this manner, theexternal display device 502 permits a caregiver or another person toview the images captured by the ophthalmoscope device 102. The exampleexternal display device 502 is displaying an image 506 of an eye and acursor 508.

The external input device 504 is a component that provides user input tothe ophthalmoscope device 102. Example types of input devices include,but are not limited to, keyboards, mice, trackballs, stylus inputdevices, key pads, microphones, joysticks, touch-sensitive displayscreens, and other types of devices that provide user input. In someembodiments, the external input device 504 is integral with the externaldisplay device 502, while in other embodiments the external displaydevice 502 and the external input device 504 are separate devices.

In some embodiments, the external input device 504 provides repositioncommands to the ophthalmoscope device 102. The reposition commandsdirect the ophthalmoscope device 102 to reposition the cursor 202 on theoverlay layer 200. In some embodiments, the reposition command includesnew coordinates for the cursor 202. In other embodiments, the repositioncommand includes a delta vector for the cursor 202. Yet otherembodiments are possible as well. Using the reposition commands, acaregiver can direct the eye of the subject S to a desired location forimaging.

In some embodiments, the external input device 504 provides imagecapture commands to the ophthalmoscope device 102. The image capturecommand directs the ophthalmoscope device 102 to capture a fundus image.Using the image capture command, a caregiver can capture a fundus imageat any desired orientation.

In some embodiments, the ophthalmoscope device 102 communicates directlywith the external display device 502 and the external input device 504.For example, in some embodiments, the ophthalmoscope device 102communicates directly with the external display device 502 and theexternal input device 504 using Bluetooth. Other embodiments arepossible as well.

FIG. 18 is another example system 540 for performing ophthalmoscopyprocedures. The example system 540 includes the ophthalmoscope device102, the external display device 502, the external input device 504, andan external computer 542. The system 540 is similar to the system 500,except that the ophthalmoscope device 102 communicates with the externalcomputer 542 rather than the external display device 502, and theexternal input device 504.

The external computer 542 is a computing device. Computing devices aredescribed in detail with respect to FIG. 1. In some embodiments, theexternal computer 542 runs a software application to communicate withthe ophthalmoscope device 102. The computing device is configured tocause the external display device 502 to display images that have beentransmitted to the external computer 542 by the ophthalmoscope device102. Similarly, the external computer 542 is configured to receive inputfrom the external input device 504 and transmits that input to theophthalmoscope device 102.

In some embodiments, the external display device 502 and external inputdevice 504 are integral with the external computer 542. For example, insome embodiments, the external computer 542 is an iPhone or iPad, bothfrom Apple Inc. of Cupertino, Calif. Yet in other embodiments, theexternal computer 542 is a different portable computing device, such asa tablet computer running an operating system like the Microsoft Windowsoperating system from Microsoft Corporation of Redmond, Wash., or theAndroid operating system from Google Inc. of Mountain View, Calif. Yetother embodiments of the external computer 542 are possible as well.

Referring now to FIG. 19, a process 570 performed using some embodimentsof the system 500 or system 540 is shown. The process 570 operates toimage the fundus of the subject S using a user directed path.

Initially, at step 572, an image of the cursor 202 is displayed on theoverlay layer 200. This step is similar to step 402 and is described inmore detail with respect to FIG. 14. The image of the cursor 202 isdisplayed throughout the process 570.

Next, at step 574, user input is received. In some embodiments, the userinput is received directly from an external input device 504. In otherembodiments, the user input is received from an external computer 542.

Next, at step 576, it is determined whether the user input is areposition command. If the user input is a reposition command, then step578 is performed to reposition the cursor. If not, then step 580 isperformed to determine whether the user input is an image capturecommand.

At step 578, the image of the cursor 202 is repositioned on the overlaylayer. In this manner, a caregiver can direct the orientation of the eyeof the subject. After step 578, step 574 is performed to receive moreuser input.

At step 580, it is determined whether the user input is an image capturecommand. If the user input is an image capture command, the step 308 isperformed to capture a fundus image as described with respect to FIG.11. If not, the step 574 is performed to receive more user input.

In other embodiments of the process 570, step 580 is not performed.Instead, the image is captured using passive eye tracking. For example,in some embodiments the process 300 is used in combination with thesteps 572-578. The process 300 is shown and described in greater detailwith respect to FIG. 11.

Although various embodiments are described herein, those of ordinaryskill in the art will understand that many modifications may be madethereto within the scope of the present disclosure. Accordingly, it isnot intended that the scope of the disclosure in any way be limited bythe examples provided.

What is claimed is:
 1. An eye fundus imaging apparatus, comprising: adisplay device; an image capture device configured to capture at leastone image of a fundus of an eye; and a control module that: displays atarget, the target indicating a desired position for the image capturedevice to capture the at least one image of the fundus of the eye;determines a delta vector between the eye and the image capture device,the delta vector corresponding to a difference in position between acurrent location of a pupil of the eye and a desired location of thepupil; and moves the target, based upon the delta vector, to positionthe eye relative to the image capture device to allow for capture of theat least one image of the fundus of the eye.
 2. The eye fundus imagingapparatus of claim 1, wherein the eye fundus imaging apparatus is ahandheld apparatus.
 3. The eye fundus imaging apparatus of claim 1,wherein the control module further displays the target for the pupil ofthe eye.
 4. The eye fundus imaging apparatus of claim 1, wherein thetarget is a cursor.
 5. The eye fundus imaging apparatus of claim 1,wherein the eye fundus imaging apparatus is a wearable apparatus.
 6. Theeye fundus imaging apparatus of claim 5, wherein the wearable apparatusincludes a display device to show the target.
 7. The eye fundus imagingapparatus of claim 6, wherein the display device includes a projectorthat projects the target.
 8. The eye fundus imaging apparatus of claim1, wherein the control module continues to calculate the delta vector toposition the eye relative to the image capture device.
 9. The eye fundusimaging apparatus of claim 8, wherein the control module continues toreposition the target to position the eye relative to the image capturedevice.
 10. A method for eye fundus imaging, comprising: displaying atarget, the target indicating a desired position for the image capturedevice to capture the at least one image of the fundus of the eye;determining a delta vector between the eye and the image capture device,wherein the delta vector corresponds to a difference in position betweena current location of a pupil of the eye and a desired location of thepupil for fundus imaging; and moving the target, based upon the deltavector, to position the eye relative to the image capture device toallow for capture of the at least one image of the fundus of the eye.11. The method of claim 10, wherein the eye fundus imaging apparatus isa handheld apparatus.
 12. The method of claim 10, further comprisingdisplaying the target for the pupil of the eye.
 13. The method of claim10, wherein the target is a cursor.
 14. The method of claim 10, whereinthe eye fundus imaging apparatus is a wearable apparatus.
 15. The methodof claim 14, wherein the wearable apparatus includes a display device toshow the target.
 16. The method of claim 15, wherein the display deviceincludes a projector that projects the target.
 17. The method of claim10, further comprising continuing to calculate the delta vector toposition the eye relative to the image capture device.
 18. The method ofclaim 17, further comprising continuing to reposition the target toposition the eye relative to the image capture device.